New Jersey features two primary climate zones: a humid subtropical climate across most of the state and a humid continental climate in the northwestern highlands. Residents enjoy an average of 2,400 to 2,800 hours of sunshine annually, with four distinct seasons shaping life across the state.

Summers are typically hot and humid, with average highs of 82–87 °F (28–31 °C) and lows of 60–69 °F (16–21 °C). Heat waves can push temperatures above 90 °F (32 °C) for roughly 25 days each summer, and occasionally exceed 100 °F (38 °C). Winters are cold, with average highs of 34–43 °F (1–6 °C) and lows of 16–28 °F (−9 to −2 °C), though northwestern areas frequently experience sub-zero temperatures. Spring and autumn bring milder temperatures and lower humidity, often with wide swings from day to day. The state spans USDA Plant Hardiness Zones 6 to 7B, accommodating diverse vegetation. Historical extremes include 110 °F (43 °C) in Middlesex County in 1936 and −34 °F (−37 °C) in Bergen County in 1904.

Precipitation is relatively uniform throughout the year, averaging 43–51 inches (1,100–1,300 mm) annually. Snowfall varies from 10–15 inches near the southern coast to 40–50 inches in the northwestern highlands, with nor’easters occasionally bringing blizzards and flooding. Severe weather events such as hurricanes, tornadoes, and earthquakes are rare but have occurred, including Tropical Storm Floyd in 1999 and Hurricane Sandy in 2012.

New Jersey is warming faster than nearly any other state in the U.S. Over the past century, average air temperatures have risen significantly, a trend attributed in part to warming of the North Atlantic Ocean. This ongoing climate change poses challenges for coastal communities, infrastructure, and natural ecosystems, highlighting the state’s need for adaptive planning and resilience strategies.